# Causes

## Machine‑tool Aspects

Machine‑tool Vibration: Vibration may occur during operation of machine‑tool components such as spindles and motors. Transmitted to workpieces and grinding wheels, such vibration causes ripples on workpiece surfaces. For example, worn spindle bearings and unbalanced motors can trigger vibration.

Insufficient Guideway Accuracy: Guideways are critical moving components of machine tools. If their straightness, parallelism and other accuracy indexes fail to meet standards, grinding wheels or workpieces will move irregularly during operation, forming ripples on workpiece surfaces.

## Grinding‑wheel Aspects

Unbalanced Grinding Wheel: Uneven mass distribution arising from manufacturing or installation generates centrifugal force when the grinding wheel rotates at high speed and induces vibration, which further creates surface ripples on workpieces.

Uneven Grinding‑wheel Wear: After long‑time operation, partial severe wear may take place on the grinding wheel, resulting in inconsistent cutting performance across its surface and ripples during grinding.

## Workpiece Aspects

Unstable Workpiece Clamping: Without firm clamping during grinding, the workpiece will displace or vibrate under grinding force and produce surface ripples.

Uneven Workpiece Material: Non‑uniform hardness and internal structure of the workpiece lead to inconsistent resistance against the grinding wheel, impair grinding stability and generate ripples.

## Grinding‑parameter Aspects

Improper Grinding Speed: Excessively high or low grinding speed may bring about surface ripples. Excessively high speed increases friction and impact between grinding wheel and workpiece and tends to cause vibration; excessively low speed leads to poor grinding stability.

Excessive Feed Rate: A large feed rate raises cutting force exerted by the grinding wheel on the workpiece and may result in surface ripples.

# Solutions

## Machine‑tool Aspects

Machine‑tool Maintenance and Commissioning: Inspect and maintain spindles, motors and other components on a regular basis. Replace worn bearings timely and perform dynamic balance correction for motors to reduce machine‑tool vibration. Meanwhile, adjust guideway accuracy to satisfy specifications.

Vibration‑reduction Measures: Install shock‑absorbing pads on the machine‑tool foundation or adopt vibration isolators to mitigate external vibration impact.

## Grinding‑wheel Aspects

Grinding‑wheel Balancing: After installation, balance the grinding wheel with balancing stands or electronic balancers to guarantee stable rotation.

Timely Dressing of Grinding Wheel: Dress the grinding wheel periodically to remove unevenly worn sections and restore a flat, sharp working surface.

## Workpiece Aspects

Optimized Clamping Method: Select proper clamping modes according to workpiece shape and dimension for firm fixation. For instance, apply center rests or follow rests for auxiliary support of slender shaft workpieces.

Workpiece Pre‑treatment: Carry out appropriate pre‑treatment such as heat treatment for workpieces with uneven material to improve homogeneity of internal structure and hardness.

## Grinding‑parameter Aspects

Optimized Grinding Speed: Select proper grinding speed based on workpiece material and grinding‑wheel characteristics. The optimal value can be determined via tests and adjustments.

Adjust Feed Rate: Reduce feed rate moderately for smoother grinding. Note that overly small feed rate will lower processing efficiency; a balance should be achieved.